1. Field of the Invention
The present invention relates to a selvage former for tucking an end of a filling into a shed of a weaving machine, comprising a bracket carrying a means for receiving the end of a filling inserted into a shed, and a means for blowing the end into a subsequently formed shed, the means for blowing being connectable by a valve actuated by a control unit to a source of compressed air.
2. Related Art
Such a selvage former is known from U.S. Pat. No. 4,957,144. The end of an inserted filling is initially retained pneumatically and then is blown by blowing orifices into a shed. The blowing orifices are provided in a tuck-in device located adjacent the side of the shed. A selvage former also is known from U.S. Pat. No. 1,426,351 wherein a filling end is received within a guide element and then is blown by a blowing means into the subsequently formed shed. The blowing means includes a nozzle disposed at an angle relative to the fabric's beatup filling to blow the filling end held in the guide element in the direction of the beatup filling. Another device is known from U.S. Pat. No. 2,267,287 wherein several nozzles each operating in a different blowing direction are used in order to deflect the end of a filling and to blow it in the direction of the beatup filling.
3. Brief Summary of the Invention
The objective of the present invention is to so design a selvage former of the described type that it may be used for any fabric.
This objective is realized in that said bracket is fitted with a minimum of one rotatable insert which may be connected to a source of compressed air and which comprises at least one blowing aperture having an adjustable position.
The selvage former may be easily matched to the fabric and/or to the filling to be woven by changing the position of the blowing aperture. The position of the blowing aperture may be changed by exchanging said insert with another one having a different blowing aperture or by locating the blowing aperture at a different location and/or in that the insert is rotatable and in particular is rotatable with respect to its angular position. This feature is advantageous when there is a change in the fabric to be woven. Also said insert may be exchanged when worn without the complete bracket or the complete selvage former being exchanged and/or disassembled.
In a preferred embodiment, the insert is fitted both with an axial duct which may be connected to a source of compressed air and with at least one substantially radially pointing blowing aperture. Such a design proves advantageous in blowing a filling end into a shed.
In a preferred embodiment of the present invention, the bracket is fitted with a guide slot for the fillings and the insert(s) is (are) mounted in front of an end of the guide slot. Advantageously at least some of the elements making contact with the fillings are fitted with wear-resistant covers. As a result, such covers may be replaced in a problem-free manner without having to replace the entire holder or the entire device of the invention. The insert may be a part that is subject to wear and may be replaced as needed.
In accordance with a further embodiment of the present invention, the bracket is fitted with a pneumatic retaining element for retaining the end of a filling. As a result, the filling may be held in a specific location from which it may be blown by the blowing aperture into the shed. This pneumatic retaining element furthermore is appropriate to hold a filling end following severance of the filling.
In a preferred embodiment of the present invention, a filling cutting system is mounted on the side of the bracket which faces away from the fabric. As a result, the length of the filling to be blown by the selvage former into the shed may be determined precisely. Advantageously, the cutting system is located at an adjustable distance from the bracket so that the length of the filling to be blown into the shed is adjustable.
In a further embodiment of the present invention, the bracket is fitted with a minimum of one blowing aperture located in the region of a side wall of the bracket facing the fabric. Such a blowing aperture makes it possible, besides blowing onto the filling end, to point one or more air jets onto the warps in order to prepare the edge of the shed, which is formed of warps, for the purpose of blowing a filling end into said shed. Advantageously a minimum of one blowing aperture located in the region of the side wall of the bracket is located in an insert that may be rotated to adjust the direction of the blowing aperture.
In a further embodiment of the invention, a drive preferably actuated by the weaving machine control is associated with at least one insert which is fitted with at least one blowing aperture which is used to insert the filling end into a shed. The insert may be adjusted by an operator via an input to the control unit after the operator has checked the selvage formed by inserting the filling into a shed. The insert adjustment also may be carried out using data generated by a pickup and transmitted to the control unit, for instance as a function of camera-recorded imaging of the inserted end of the filling.